The female hippo, named Pelagia, was euthanised after her health deteriorated, the zoo said in a Facebook post.
Pelagia was born in 1985 at the Wrocław Zoo in southwestern Poland and was originally named Isaura, after a character in a popular Brazilian television series at the time, Polish state news agency PAP reported.
In 1986, she was transferred to the Paris Zoo, where she was later renamed Pelagia.
After spending 25 years in Paris, she was slated for relocation to Algeria but was ultimately transferred to Germany before arriving in Warsaw in 2011.
At Warsaw Zoo, Pelagia lived with a younger male hippo named Hugon.
"Pelagia wouldn’t let anyone push her around" and was "exceptionally intelligent," zoo officials said, adding that her keepers had to work hard to earn her trust.
They described her as a "special hippopotamus" who helped staff better understand the care of aging animals.
The zoo said the decision to euthanise her was made after careful monitoring of her condition.
"Euthanasia is never easy, but we knew this was the moment to let her go with dignity," officials said.
Zoo staff referred to Pelagia as "the queen," saying she had relinquished "her crown and title as the oldest hippopotamus in Poland."
"Now she can rest in peace in her private pool, where no one disturbs her tranquility," they said.
Hippopotamuses can live up to about 40 years in the wild and up to 50 years in captivity.
Despite their size, they can run at speeds of up to 30 kph. Although they spend much of their time in water, hippos cannot swim, instead moving by pushing off the riverbed.
Despite their pig-like appearance, hippopotamuses are most closely related to whales and dolphins.
(pm/gs)
Source: PAP